A dropped cigarette butt, a chewed-up piece of gum, a stray hair. Artist Heather Dewey-Hagborg uses DNA she's picked up around New York City to generate 3-D portraits of those who left their trash behind. This rendering of a brown-eyed man of Eastern European descent came out of a cigarette butt Dewey-Hagborg found in Brooklyn, N.Y.

Heather Dewey-HagborgHeather Dewey-Hagborg

Heather Dewey-Hagborg was sitting in a therapy session a while ago and noticed a painting on the wall. The glass on the frame was cracked, and lodged in the crack was a single hair. She couldn't take her eyes off it.

"I just became obsessed with thinking about whose hair that was, and what they might look like, and what they might be like," she says.

On the subway ride home, she noticed all of the insignificant things people left behind — a dropped cigarette butt, a chewed-up piece of gum. Like the hair stuck in the frame, she wondered how much genetic material might have been tossed away with the trash.

So Dewey-Hagborg started collecting these forgotten "artifacts," as she calls them, and bringing them back to a lab to analyze their embedded genetic material.

Yet it might seem Dewey-Hagborg would be more comfortable in a studio than a laboratory. She's an artist; a doctoral student in Information Art at Rensselaer Polytechnic Institute in Troy, N.Y. For her most recent project, though, much of the creative process takes place in front of a centrifuge, wearing latex gloves, deep in the map of the human genome.

In short, Dewey-Hagborg extracts DNA from these samples of trash and turns that information from code into life-sized 3-D facial portraits resembling the person who left the sample behind. She can code for eye color, eye and nose width, skin tone, hair color and more.

She starts by cutting up her sample, sometimes the end of a cigarette, thin slices of a chewed wad of gum, sometimes hair, and incubates the sample with chemicals to distill it into pure DNA.

She then takes that DNA, and matches the code with different traits on the genome related to the way human faces look.

"That's a very tiny subset of all of the things that we know about the entire mapping of the human genome, " she says.

Next, she sends the DNA to a sequencing company that sends her back a text file full of A, C, Ts and Gs — remember those from biology class? Those are the four nucleic acid bases that DNA is made out of.

She then reads that information in a program she designed herself, translating the code into traits, then using those traits to build a 3-D model of a face. Dewey-Hagborg can determine ethnicity, gender, even a tendency to be overweight.

But even all of that can't give her the whole picture. Much of the information is still missing, and Dewey-Hagborg has to fill in the gaps. She compares that part of the work to a sketch artist. "This person is more likely to be overweight, to have pale skin, to have freckles, blue eyes, how do I interpret this?"

People often ask her how accurate the portraits are. Of course, she has no way of knowing. After all, she collects these items from anonymous sources. But she did start off with her own portrait based on her own DNA. She exhibited that at an art and technology space in Chelsea.

"Half of the people would say, 'Wow! It looks just like you!'" she says. "The other half would say, 'Wow! It looks nothing like you!" The portraits are subjective in a big way, she acknowledges, but says much of the information is solidly based in data.

Though she started this project in part to "open up the conversation about genetic surveillance," she says, it's taken on another purpose. Right now she's working with the Delaware medical examiner's office to try to identify a woman in a 20-year-old unsolved case by using some of the victim's remains to build a 3-D portrait of her. She's six weeks away from finishing the process, when investigators will, for the first time, have some idea of what the victim looked like before her death.